COOKWORTHY'S PROCESS. PLYMOUTH CHINA WORKS. 231 



advantages of painting and glazing on a soft biscuit, as they are 

 very obvious to any one, ever so little used to pottery. 



" In regard to burning, I have to remark, that by all the experi- 

 ments we have made, the north of England kilns, where the fire is 

 applied in mouths on the outside of the kilns, and the fuel is coal, 

 will not do for our body, at least when it is composed of the mate- 

 rials of Tregonnin Hill. 



" In those kilns especially, when bags are used, there is no pas- 

 sage of air through the middle of the kiln ; and a vapour, in spite 

 of all the care that can be taken, will either transpire through the 

 bags, or be reflected from the crown, which will smoke and spoil 

 our ware, though it doth not appear to affect other compositions. 

 How true this remark may be, with regard to the St. Stephen's 

 materials, I cannot determine, as they have not yet been tried in a 

 kiln. The only furnace or kiln which we have tried with any 

 degree of success, is the kiln used by the potters who make brown 

 stone. It is called the 36-hole kiln. Wood is the fuel used in it. 

 They burn billets before and under it, where there is an oven or 

 arch pierced by 36 holes, through which the flame ascends into the 

 chamber which contains the ware, and goes out at as many holes 

 of the saine dimensions in the crown of the furnace. The safe- 

 guards at bottom stand on knobs of clay, which won't melt, about 

 two inches square, and two inches and a half or three' inches 

 high ; by which means more of the holes are stopped by the 

 bottoms of the safeguard, but the air and flame freely ascend, and 

 play round every safeguard ; by which means those tingeing 

 vapours, which have given us so much trouble, are kept in con- 

 tinual motion upward, and hindered from penetrating and staining 

 the ware. 



" Experience must determine the best form and way of using 

 this kiln. 'Tis the only desideratum wanting to the bringing of 

 the manufacture of porcelain, equal to any in the world, to perfec- 

 tion in England. 



" Caulin pipe-clay and a coarse unvitrifiable sand make excellent 

 safeguards." 



The experiments on the Cornish materials having been 

 perfectly successful, Cookworthy established himself as a 

 china manufacturer at Plymouth, where the buildings still 

 exist, and are known by the name of the " China House." 



In these works Cookworthy prosecuted his new art with 



